No Display After Power Surge

Alright, this isn't going to sound like the brightest thing, but here goes... I run my system on a 110 power supply. I went to a friend's place to do some work on my system, and went to use his setup to plug in my computer. Not realizing he uses a 220 power supply... Well, you can guess what happens from there. FLASH! POP! No more PSU. Alas, but at least the problem was obvious and easily repaired. Or so I thought.

After replacing the PSU, I attempt to start up the computer. It SOUNDS like it starts up fine. No beeps, no power struggle, nothing... Just normal operation. Unfortunately, the display seems to show nothing. At first, I thought of the possibility of a graphics card blowing out (even though there were no beeps), so I replaced it, to no avail. I've also tried a couple of different monitors (just in case the power outtage also took out the connected monitor). I've yet to test the northbridge on it, but will soon (by placing a network card in a PCI slot and seeing if it lights up, which shouldn't really matter, as the northbridge typically effects the PCU as well, which seems to still be running). However, in the case that such is not the problem, what else could be going wrong here? It seems unlikely that just the AGP slot was fried.

I was hoping for any kind of suggestion other than the AGP being fried... But, I guess, easier than that, I could just get a PCI graphics card. Still, hoping it might be something repairable.